This invention relates to a Teflon-bonded catalyst system for the detection and elimination of hydrogen gas in sealed equipment housings. In particular, it relates to a catalytic system for use with batteries.
There are many military and civilian applications in which a battery is incorporated into the hermetically or partially-sealed housing of electrical, electronic or mechanical equipment. Since most batteries produce some hydrogen gas while standing or during discharge or re-charge, an explosive hydrogen-air mixture can eventually result and be ignited by a spark or arc from the equipment in the housing. Examples thereof are magnesium or zinc primary cells used with radio sets and other communications equipment and rechargeable lead-acid, silver-zinc or nickel-cadmium cells used with communications equipment, sensor equipment, internal combustion motors or electrical relays.
For such applications, it is useful to have a non-detonating and reliable catalyst which will keep the concentration of hydrogen below the explosive limit (4.1%) of reaction with the oxygen in the air, and it is further advantageous to have a simple and non-detonating detector that will give warning of the presence of an unexpected large concentration of hydrogen. The detector may be used either by itself, to detect hydrogen without attempts at removal, or it may be used with a hydrogen-removal catalyst, to warn of the presence of hydrogen even though the catalyst itself will eventually eliminate the hazard.
The aforementioned "unexpected large concentration of hydrogen" could result from battery deterioration or failure of a structural member intended to impede the flow of hydrogen from the source to the electrical, electronic or mechanical equipment.
A specific problem solved by the present invention is the detection and removal of hydrogen from an Army AN/PRC-77 radio set. In this radio, very large volumes of H.sub.2 are produced by the battery commonly used therewith. Most of this hydrogen escapes to the outer atmosphere through a vent in the battery box. However, some of the hydrogen can leak through the battery connector and find its way into the "sealed" electronics compartment. It appears that a leakage rate as high as 200 cc of H.sub.2 per day is possible in this application if the connector is faulty. Even higher leakage rates will occur if the vent fails. With the 3400 cc. void volume of the electronics compartment, the entry of only 139 cc. of H.sub.2 (a concentration of more than 4.1 volume percent H.sub.2) could result in an explosive mixture. Hence, such leakage presents serious problems.
Accordingly, one of the objects of the present invention is to provide a system for the detection of hydrogen gas in sealed equipment housings.
Another object of the invention is to provide a catalyst system which eliminates hydrogen gas so as to prevent potential explosions.